docs: def _get_stddevs(self, sites, rup, C, stddev_types, ln_y_ref, exp1, exp2):
          """
          Returns the standard deviation, which is fixed at 0.65 for every site
          """
          ret = []
          for stddev_type in stddev_types:
              assert stddev_type in self.DEFINED_FOR_STANDARD_DEVIATION_TYPES
              if stddev_type == const.StdDev.TOTAL:
                  # eq. 13
                  ret.append(0.65 * np.ones_like(sites.vs30))
          return ret